What they doing? Pumping liquefied sand to combat coastal erosion?

Edited By Pete Rimmer on 03/08/2019 15:40:29

They did something very similar to this at Heacham, some years ago, where sand had been scoured away some 6 feet.in places. It is quite an undertaking.

After a few storms, much of the sand was relocated.

The Peterborough Engineering Society had a lecture from someone from, I think, the Kirton and Lindsey sector of Environment Agency, about this time. He showed that after a LOT of experimenting, the best and most effective method is rock armouring. A storm will shift those big 4 ton concrete tetrapods, but not big rough lumps of rock.

The hards (slips ) have been protected with rock armouring for several,m years, and the scouring of sand does not seem to happen so badly.

Howard

I remember riding a motorbike under one of those tubes. It was near Folkstone when the channel tunnel was being built. The ship was about a mile offshore and they were pumping shingle and gravel to raise the level of the rail terminal. They were pumping for months. The pipe was about a metre diameter and came up the beach and went straight up and over the road with about 20 feet clearance. I don't know how they returned the water to the sea.

Edited By old mart on 03/08/2019 21:53:05

There are areas of the English Channel and North Sea floors thickly carpeted with sand and gravel, washed in by rivers, or left when the Channel was a river valley in the present Ice Age's Last Glacial Maximum.

Some of this gravel is collected by suction-dredgers such as illustrated above, for building aggregate (I assume it has to be washed to remove the salt) and one such deposit is off the Kent and Sussex coast.

Maybe 15 years ago now, this trade became the focus of a genuine (not campaigners&#39 environmental concern, but not as you might expect, over destroyed sea-floor wildlife and habitats. At least, not as far as my involvement goes.

Instead a marine-biology department somewhere I know not, were worried about the underwater noise of the dredging driving fish and mammals away. So the firm for I worked was sub-contracted to take underwater sound-spectra, by amplitude with frequency, at planned points around the dredger, whose crew were perfectly happy about it all. Two of us – scientist and I as lab assistant – spending the day on a small work-boat owned by an environmental-surveying company, circling the dredger at set distances and taking hydrophone readings.

The dredger was noisy enough on the surface, with the continual roar of its engines and of gravel and water being pumped aboard. Big cascades of sand-coloured water poured from the hold overflows, creating a plume of aquatic "fog" drifting down-Channel on the strong tidal stream.

The skipper of the chartered boat pointed to the plume and remarked, " I'd have thought they'd worry far more about that silt settling to the sea-bed and choking the tiny animals living in it! "

He had a point, but if " they " were also asking that question, it was to others, outside of my firm's remit and expertise.

Our manager duly sent in the report. I never learnt how it was received or what became of the customer's study.